Nelson was drafted by the Bruins in 2006, while playing in the WHL. In 2007-08, he scored 25 goals and 61 points in the WHL, while recording 152 penalty minutes. His solid numbers earned him a callup to the AHL for the 2008-09 season, where he scored 7 points in 59 games. He was retained by the Bruins after training camp for the 2009-10 season.